ios8 crash about addObserver:

Question

An crash happened on me since update to xcode6 iOS8. The log is " 2014-09-28 14:53:34.069 ViewDemo[35448:3262351] * Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'An instance 0x7f9750c1c410 of class RedView was deallocated while key value observers were still registered with it. Current observation info: ( Context: 0x0, Property: 0x7f9750c1b910> )' * First throw call stack: (

0   CoreFoundation                      0x00000001022e93f5 __exceptionPreprocess + 165
1   libobjc.A.dylib                     0x0000000101f82bb7 objc_exception_throw + 45
2   CoreFoundation                      0x00000001022e932d +[NSException raise:format:] + 205
3   Foundation                          0x0000000101b65af2 NSKVODeallocate + 317
4   UIKit                               0x000000010273fc97 -[UIView(Hierarchy) removeFromSuperview] + 633
5   UIKit                               0x0000000102733d19 -[UIView dealloc] + 404
6   libobjc.A.dylib                     0x0000000101f978cd _ZN12_GLOBAL__N_119AutoreleasePoolPage3popEPv + 591
7   CoreFoundation                      0x00000001021e0346 _CFAutoreleasePoolPop + 22
8   CoreFoundation                      0x0000000102214473 __CFRunLoopRun + 2051
9   CoreFoundation                      0x0000000102213a06 CFRunLoopRunSpecific + 470
10  GraphicsServices                    0x00000001058b19f0 GSEventRunModal + 161
11  UIKit                               0x00000001026d5550 UIApplicationMain + 1282
12  ViewDemo                            0x0000000101a53657 main + 103
13  libdyld.dylib                       0x0000000104861145 start + 1

) libc++abi.dylib: terminating with uncaught exception of type NSException

"

This is log I reproducted from my demo. It looks like the addObserver action break the relationship about superview and subviews. When the superview dealloc the subviews did not dealloc first.

Did anyone has ides about this?

You should remove observer from your RedView in dealloc method. — arturdev
had a similar issue, try to log the object hashes when adding and when removing the observers. It is possible you add an observer twice and only remove once (and may not even be able to remove it twice) — NikkyD
Where are you adding/removing the observer? (i.e. where in the code). — Ethan G

JackyJohnson JackyJohnson · Accepted Answer · 2014-09-28T08:16:09

This exception is usually thrown when you are destroying an object that has an observer previously added to it.

To resolve the problem you need to call removeObserver:forKeyPath: on that same object before calling the method that destroys that object.

ios8 crash about addObserver:

1 Answers